Acoustically absorptive materials are used to dampen noise in commercial, industrial and residential settings. Reduced noise in commercial and industrial areas creates a healthier and more productive work environment, and sound dampening materials in the family home can make for more pleasant and relaxing surroundings.
Acoustically absorptive materials consist mainly of porous absorbers and membrane absorbers. Porous absorbers include mineral fibers, such as fiberglass insulation, foams, such as melamine foam, carpeting, textiles, insulators, such as cotton insulation, and wood fiber board products. The absorptive effect of the porous absorbers is based on the fact that sound is able to enter the open structures of the material where, due to the friction of air particles, the sound energy is converted into thermal energy at the surface of the pores. Porous absorbers achieve their best effect at medium and high frequencies.
While porous absorbers may be effective at sound absorption, they typically do not present an aesthetically pleasing appearance. Although melamine foam and cotton insulation products are available in different colors, they do not have facings capable of retaining an aesthetically acceptable printed image. Melamine foam is, however, available in a variety of surface patterns, including a pyramid pattern available from Pinta Acoustic, Inc. under the SONEXpyramid brand, whereas fiberglass and cotton insulation are generally available only in flat panels. Fiberglass panels are normally wrapped in an acoustically transparent fabric which can be obtained in solid colors or imprinted with a pattern.
Membrane absorbers create and employ an associated air space to absorb sound. The combination of a membrane absorber and adjacent air space works as a mass-spring system in which mass is provided by the membrane and the associated air space and a spring property results from the spring-like quality of the membrane and the stiffness of the air together. Examples of membrane absorbers are acoustic tile ceilings, gypsum board walls and ceilings, and stage structures. Membrane absorbers have been combined with a porous absorber disposed inside the associated air space to provide sound absorption through a wider range of frequencies.
Some sound absorbing systems use stretched fabric acoustic absorbers. Several fabric acoustic absorbers are available, such as from Wall Technology, Inc. under the Eurospan® brand, from Stretchwall Installations, Inc. under the Stretchwall® brand, from Clipso S.A. Corporation under the Clipso® brand, and from Novawall Systems, Inc., under the Novawall® brand. Sound absorbing systems using such stretched fabric acoustic absorbers are typically field installed using proprietary frames over which the fabric is stretched, the frames frequently having grooves into which the fabric is tucked to tension it. These systems are generally mounted on an entire wall or ceiling, as opposed to a smaller discrete area, using mounting systems directed to covering entire wall surfaces. A small air space between the insulation and the fabric in these prior art systems allows the fabric to be stretched and ensures a flat finish.
Traditional acoustic panels generally use fabrics that are not suitable for printing, but which can take on a solid color, although it is known to use patterned fabrics. A system consisting of a printed fabric attached to an aluminum frame with a flat foam acoustically absorbent panel inside the frame is available from CCS Digital Fabric, GmbH under the Fabric_Frame® brand.
None of the prior art acoustically absorbent systems provides for the ability to effectively tune the sound absorbing qualities of the system to dampen selected sound frequencies. Prior art wall systems having sound absorbing capabilities typically do not have a front surface able to accept a printed graphic image. In addition, no prior art sound absorbing wall system exists that provides a product suitable for installation in a discrete area smaller than the full expanse of an entire wall or ceiling. There is, therefore, a need to develop an acoustical wall panel system with improved sound absorbing capabilities that is appropriate for hanging on a wall surface or a similar type of readily removable installation.